This paper focuses on the discussion about the briefest reduct of Rough Sets which is extracted by genetic algorithm. The fitting function is designed by the combination of the relying degree of RS and sum of seeds which is the attributes of data. Genetic Algorithm operator is applied and the algorithm is tested by UCI database. After the analysis and discussion, RGA and RGA_2 have been proved available. In the discussion, crossover and mutation probability have got a experienced number. Increasing the sum of seeds, and saving the last generation optimized seeds can be improving the efficiency of algorithm.